Alloy steel of high-surface stability and articles made therefrom



Patented Sept. 29, 1925.

UNITED STATES PATENT. OFFICE PERCY A. E. ARMSTRONG, OF LOUDONVILLE, AND RALPH P. DE VRIES, OF NEWTON- VILLE, NEW YORK, ASSIGNORB, IBY DIRECT AND MESNE ASSIGNMENTS, TO LUD- LUM STEEL COMPANY, 01' WATERVLIET, NEW YORK, A. CORPORATION 01' NEW JERSEY.

ALLOY STEEL OI HIGH -S URFACE STABILITY AND ARTICLES MADE THEREFROM.

1T0 Drawing. Continuation application filed January 10, 1921, Serial No. 436,335. This application flied January 14, 1921. Serial No. 487,353.

To all whom it may concern:

Be it known that we, PnRcr A. E. ARM- srnonc, a subject of the King of Great Britain, and a resident of Loudonville, conni ty of Albany, and State of New York, and RALPH P. De Vmns, a citizen of the United States and a resident of Newtonville, county.

of Albany, and State of New York, have invented a new and useful Alloy Steel of 1 High-Surface Stability and Articles Made Therefrom, of which the following is a specification.

This application is a continuation of our rior application, Serial No. 436,335, filed aiiuary th, 1921, and having the same tit e. i

Our invention relates to an alloy steel containing iron, carbon, chromium, silicon and nickel in proportions as stated below; and having high surface stability, that is to say, a high degree of resistance to staining, corroding, oxidizin and the like agents. The mvention a so relates to articles made from such alloy steel of high surface stability, of which an article of cutlery is a good example.

The principal part of the alloy is iron.

. The carbon is preferably kept low, that is to say, under about .50%, but may be from 80 about .05% to about .60%, according to the hardness required in the tool or other article to be produced. The chromium of the alloy, which also contains nickel and silicon, is preferably from about 5% to about 9%. Less than 5% chromium, though useful, does not produce material of extremely high surface stability, and above 9% of chromium, nickel is of relatively small importance from the standpoint of surface stability, though sub stantial proportions of silicon can be used to very good advantage.

With chromium from about 5% to about 9%, sufficient nickel and silicon is incor- 4 porated to make up a total chromium-nickelsilicon content of about 12% to about 15%.

The proportions of chromium, silicon and nickel in a number of samples which were found be highly resistant to oxidation, to the act on of nitric acid, and to the staining or tarn1shing tendencies of vinegar and fruit aclds, are glven in the following table:

Chromium Silicon Nickel gf f Per cent Per cent Per cent Per cent 6. 44 4. 01 1. 76 1a 21 0.56 a. 85 2.80 13. 21 7. 56 2.96 2.96 13.48 6. 12 4. 5o 2. 88 13. 56 o. 64 4.46 3.40 14.50 5. 28 4. 70 4. 72 14. 70

increases from about 5% to about 9%, the

quantity of nickel and silicon taken-together in general decreases so as to make up a total .of chromium-nickel-silicon of about 12% to about 15%. Thus with 5% of chromium the nickel and silicon taken together may be from about 7% to about 10%; and with 9% of chromium, nickel and silicon taken together may be from about 3% to about 6%. A good example of the low chromium material may contain: Chromium about 5%, nickel about 5% and silicon about 5%, or a total of 15% of chromium, nickel and silicon taken together.

Alloy steel such as described and containing iron, carbon, chromium, nickel and silicon, to give best stable surface qualities, should be heat treated, as by heating to from about 1750 F. to about 1950 F.

preferably about 1900 F., and quenching in oil, water, or other quenching medium. The alloy steel may be drawn to suit the purposes for which the alloy is to be used,

generally a drawing temperature of from about 500 to 800 is preferable; This alloy steel may be mechanicall Worked, as by forging, rolling, or the li e operations, or

may be cast and used in the cast condition.

This alloy steel is useful for many purposes where high resistance to ox1dat1on hot or cold, and to the action of corrodmg, tarnishing or the like agents is of importance. Among such uses, in add1t1on to articles of cutlery or other tools for which such material is particularly well adapted, since it readily takes and holds a good cutting edge and a high polish and is extremely res1stant to rust an to tarnish, such as caused in ordinary steels by vinegar, fruit juices and the like, we may mention out of many others, the following: valves formternal combustion engines, blades for gas and steam turbines, electrical heating elements to be run at relatively low temperatures up to about 1400 F., hardware metal cutting tools for withstanding rapid dulling at moderately high temperatures, say up to about 600? F., etc.

Molybdenum up to about 1% can be incorporated with t e alloy, the proportion of molybdenum which can be carried increasing with increase in the chromium content. Molybdenum in cutlery blade material produces increased hardness, and the preferable proportion of molybdenum, when-used, is about 25% to about .50%. The heat treat ment is not materially changed by such addition of molybdenum. Various other ele- .ments than as enumerated may be. incor porated with the new improved alloy steel, as long as same are not detrimental to the high stable surface characteristics. Same should not in general exceed a total of about 5%.

In the production of our improved alloy steel, cheap high-carb0n ferro-chromium can be utilized to good advantage, since so little ferro-chromium is re uired in making up the melt that the use of ferro-chromium having a relatively high carbon is permissible and the carbon in the alloy still be within the desirable low range. The use of ferro-chromium made by silicon reduction may result in still further economy.

It is to be understood that our invention is not to be limited except as pointed out in our claims, and that the examples given are for the purpose of affording an understanding of the invention and not for its limitation.

We claim:

1. Alloy steel of high surface stability containing carbon about .05% to about .60% chromium about 5% to about 9%, nickel and silicon, the silicon being over 1%, and the silicon and nickel taken together being sufficient to make up a total chromium-nickelsilicon content of about 12% to about 15%, and the principal portion of the remainder iron.

2. Alloy stee f high surface stability containing carbo about .05% to about .50%, I

ing at least e ual to oneuarter of the silicon and nicke taken toget er, and the principal ortion of the remainder iron.

3. Alloy steel of hi h surface stability consisting of iron, car 11 about .05% to about 50%, and from about 12% to about 15% of chromium, nickel and silicon taken together, the nickel content bein at least oneuarter of the silicon and nic e1 taken toget er and the silicon content being over 1%.

4. Alloy steel of hi h surface stability containing 1215% of c romium nickel and silicon taken to ether,'with nickel from 2% to 5% silicon from 2.5% to 5%, and chromium 5% of carbon not to exceed .6%, and the principal part of the remainder iron.

5. Alloy steel of high surface stability containing chromium about 5% up to about 9%, and also containing silicon and nickel the nickel bein silicon and Die el taken together and the nickel and silicon taken together from about 7% or 10% to about 3% or 6% as the chromium is increased from its lower to its up er limit.

6. Articles of high stable surface character made from the alloy steel of claim 1.

7. Articles of high stable surface character made from the alloy steel of claim 2.

8. Articles of high stable surface character made from the alloy steel of claim 3.

9. Articles of high stable surface character made from the alloy steel of claim 4.

10. Articles of high stable surface character made from the alloy steel of claim 5. 11. Forged, hardened and tempered tools of 'highly stable surface character made from the alloy steel of claim 1.

12. Forged, hardened and tempered tools of highly stable surface character made from the alloy steel of claim 2.

at least one-quarter of the.

(205%, an appreciable proportion 13. Forged, hardened and tempered tools I of highly stable surface character made from the alloy steel of claim 3.

14. Forged, hardened and tempered tools of high stable surface character made from the .alloy steel of claim 4.

15. Forged, hardened and tempered tools of highly stable surface character made from the alloy steel of claim 5.

16. Articles of cutlery of highly stable surface character made from the alloy steel surface character made from the alloy steel 10 of claim 1. of claim 4.

17. Articles of cutle of higlgllf stable 20. Articles of cutler of highl stable surface character made om the 0y steel surface character made om the a 0y steel of claim 2. of claim 5.

18. Articles of cutler of highl stable In testimony that we claim the foregoing, surface character made om the a 0y steel we have si ed our names hereto. of claim 3. ERCY A. E. ARMSTRONG.

19. Articles of cutlery of highly stable RALPH P. DE VRIES; 

